Roll presses have been widely used in the technical field, and their intended uses can substantially be divided into three groups, i.e., briquetting, compacting and crushing. In all of the three applications the press rolls exert a more or less great pressure load on the materials to be processed. Depending on the profiles of the press rolls, there will be a sliding load on the roll surface in addition to the pressure load. The intensity of the sliding load substantially depends on the amount of the pressure load on the rolls, the profile of the roll surface and the properties of the materials to be processed. Such a load may cause severe wear on the rolls, especially in the case of great pressing forces.
High-alloy steels have especially been used in the prior art for reducing wear during briquetting and compacting, deposit welding during compacting and briquetting and crushing. With these kinds of wear protection, however, a considerable decrease in the service life was observed whenever especially strongly abrasive materials, such as glass powder, metallurgical slag or iron or non-ferrous metals had to be processed. As far as crushing is concerned, an autogenous wear protection is known in the case of which the roll surface is covered by particles of the material to be processed that are deposited into the spaces between knobs arranged on the roll surface. Such an autogenous wear protection is not suited for briquetting and does not prevent the embedded, fine-grained particles of the material to be processed from bursting. As far as deposit welding is concerned, there are restrictions imposed by the process with respect to the alloy composition of the welding material.
A generic roll press, especially a pulverizing roll, is known from EP-A-0516952. This document describes a roll press in which numerous basic bores into which pin-shaped material pieces are inserted are arranged in the circumferential area. The main part of a respective pin-shaped material piece is located in the basic roll body while the rest projects from the body. The spaces of the pin-shaped material pieces projecting in hedgehog fashion on the basic roll body can be filled with a ceramic material mixed with plastics. Since the wear-resistant material pieces wear normally at a slower pace than the material in the spaces, a profiled roll surface is formed during operation. The advantage is an improved introduction power and thus the achievement of increased throughput. The production of such known roll presses is, however, very time consuming due to the provision of the numerous basic anchorage holes in the basic roll body and thus entails great costs. Furthermore it is very likely that pins will escape with this type of solution.